forked from osmocom/wireshark
112 lines
3.0 KiB
C
112 lines
3.0 KiB
C
/* frequency-utils.c
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* Frequency conversion utility definitions
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*
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* $Id$
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*
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* Wireshark - Network traffic analyzer
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* By Gerald Combs <gerald@wireshark.org>
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* Copyright 2007 Gerald Combs
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#ifdef HAVE_CONFIG_H
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# include "config.h"
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#endif
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#include <glib.h>
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#include "frequency-utils.h"
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typedef struct freq_cvt_s {
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guint fmin; /* Minimum frequency in MHz */
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guint fmax; /* Maximum frequency in MHz */
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gint cmin; /* Minimum/base channel */
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gboolean is_bg; /* B/G channel? */
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} freq_cvt_t;
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#define FREQ_STEP 5 /* MHz. This seems to be consistent, thankfully */
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/* From "802.11 Wireless Networks: The Definitive Guide", 2nd Ed. by Matthew Gast */
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static freq_cvt_t freq_cvt[] = {
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{ 2412, 2472, 1, TRUE }, /* Table 12-1, p 257 */
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{ 2484, 2484, 14, TRUE }, /* Table 12-1, p 257 */
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{ 5000, 5995, 0, FALSE }, /* Table 13-1, p 289 */
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{ 4920, 4995, 240, FALSE } /* Table 13-1, p 289 */
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};
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#define NUM_FREQ_CVT (sizeof(freq_cvt) / sizeof(freq_cvt_t))
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#define MAX_CHANNEL(fc) ( (gint) ((fc.fmax - fc.fmin) / FREQ_STEP) + fc.cmin )
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/*
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* Get channel number given a Frequency
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*/
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gint
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ieee80211_mhz_to_chan(guint freq) {
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guint i;
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for (i = 0; i < NUM_FREQ_CVT; i++) {
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if (freq >= freq_cvt[i].fmin && freq <= freq_cvt[i].fmax) {
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return ((freq - freq_cvt[i].fmin) / FREQ_STEP) + freq_cvt[i].cmin;
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}
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}
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return -1;
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}
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/*
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* Get Frequency given a Channel number
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*/
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guint
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ieee80211_chan_to_mhz(gint chan, gboolean is_bg) {
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guint i;
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for (i = 0; i < NUM_FREQ_CVT; i++) {
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if (is_bg == freq_cvt[i].is_bg &&
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chan >= freq_cvt[i].cmin && chan <= MAX_CHANNEL(freq_cvt[i])) {
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return ((chan - freq_cvt[i].cmin) * FREQ_STEP) + freq_cvt[i].fmin;
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}
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}
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return 0;
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}
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/*
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* Get channel representation string given a Frequency
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*/
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gchar*
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ieee80211_mhz_to_str(guint freq){
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gint chan = ieee80211_mhz_to_chan(freq);
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gboolean is_bg = FREQ_IS_BG(freq);
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if (chan < 0) {
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return g_strdup_printf("%u", freq);
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} else {
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return g_strdup_printf("%u [%s %u]", freq, is_bg ? "BG" : "A",
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chan);
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}
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}
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/*
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* Editor modelines
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*
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* Local Variables:
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* c-basic-offset: 4
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* tab-width: 8
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* indent-tabs-mode: nil
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* End:
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*
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* ex: set shiftwidth=4 tabstop=8 expandtab:
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* :indentSize=4:tabSize=8:noTabs=true:
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*/
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